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West Pacific/2015/09W/Archive/33
Public advisory TYPHOON CHAN-HOM PUBLIC ADVISORY NUMBER 33 WIKI-HURRICANES FORECASTING CENTER 12:00 PM JST WED JUL 08 2015 ...CHAN-HOM GRADUALLY GAINING STRENGTH AFTER HIATUS WITH TEMPORARY SLOWDOWN... SUMMARY OF 12:00 PM JST...0300 UTC...INFORMATION ------------------------------------------------------------------- LOCATION...19.5N, 133.7E CENTER POSITION CONFIDENCE: HIGH ... ± 15 MI... 25 KM ABOUT 600 MI...965 KM SE OF NAHA, JAPAN MAXIMUM SUSTAINED WINDS...90 KT...105 MPH...165 KM/H MINIMUM BAROMETRIC PRESSURE...955 MB...28.20 INCHES PRESENT MOVEMENT...WNW AT 2 KT...2 MPH...4 KM/H VARIABLE DISCUSSION AND 48-HOUR OUTLOOK --------------------------------------------- At 12:00 pm JST, the center of Typhoon Chan-Hom was situated near 19.5N, 133.7E, or about 600 miles (965 kilometers) southeast of Naha, Japan. Maximum sustained winds were 90 knots (105 mph, 165 km/h), with higher gusts. The minimum barometric pressure was 955 millibars (hPa; 28.20 inHg), and the cyclone was tracking west-northwestward at 2 knots (2 mph, 4 km/h). Conditions are expected to remain favorable for Chan-hom to continue strengthening steadily over the next two days as the typhoon tracks without much inhibition towards the southern Ryukyu Islands. NEXT ADVISORY ------------------- Next complete advisory at 06:00 pm JST. $$ Forecaster TheAustinMan Discussion TYPHOON CHAN-HOM DISCUSSION NUMBER 33 WIKI-HURRICANES FORECASTING CENTER 12:00 PM JST WED JUL 08 2015 Convective pulses continue within the large central dense overcast of Chan-hom, which has been attempting to build some sort of solidified convective strucutre about the eye. A 0034z AMSU microwave pass indicated that Chan-hom possessed a complete eyewall, but convection was heavily weighted towards the south, with the circulation to the north and northwest of the center virtually devoid of any deep convection. Nonetheless, Chan-hom continues to exhibit a very robust circulation, taking up quite a considerable portion of the Philippine Sea. Sprawling rainbands remain evident in the southern semicircle of the typhoon, and impressive cirrus outflow bands continue to flow equatorward and poleward. Water vapor imagery depicts a swath of relatively drier air dominating the area devoid of convection north of the center, but animated imagery indicates that this air is slowly being pushed out, or at least moistening slightly. Given the complete eyewall depicted on imagery and continued attempts to build convection, the intensity for this advisory has been raised to 90 knots, in agreement with CIMSS-ADT which is returning T5.0/90kt. However, there remains quite a spread with SAB returning T4.5/75kt still and other SATCON members returning estimates higher than 100 knots. Even still, this intensity estimate could still be on the upper-end of Chan-hom's potential intensity given its rather ragged appearance. Chan-hom's forward speed as been quite erratic over the past few hours, and although the storm's generally west-northwestward motion is being driven by an extention of the subtropical ridge out to the East China Sea, the storm's massive size has allowed the internal circulatory structure to play a significant role in the storm's motion, with convective surges dictating the pace of Chan-hom, with several slow-downs and accelerations noted over the morning into daylight hours. Overall, Chan-hom is expected to track slowly towards the East China Sea. Models are shifting in the long-term to a recurve scenario, which would suggest a progressing trough taking Chan-hom into the vicinity of Shanghai and Ningbo before curving it towards the Yellow Sea. Given how shift-happy the models have been in terms of the long-term track for Chan-hom, the new WHFC forecast track reflects this thinking but is conservatively moving northward. Chan-hom currently lies in 10-20 knot shear which does not appear to be displacing convection too much. However, wind shear is expected to increase temporarily over the next day, which could slow intensification down some. The most optimal conditions are expected to come in a small window from around 36 to 48 hours, where shear is expected to decrease and temperatures remain warm. During this time, Chan-hom should be able to intensify further, but the storm's immense size might be a detriment to the storm's intensification, so the peak intensity suggested by this advisory has been scaled down some. Whatever intensity Chan-hom gains at this point will determine its ultimate landfall intensity as sea surface temperatures decrease thereafter up to the coast. Post-landfall, Chan-hom should weaken quite considerably over land. INIT 08/0300Z 19.5N 133.7W 90 KT 105 MPH 12H 08/1200Z 21.2N 131.2W 95 KT 110 MPH 24H 09/0000Z 22.8N 129.3W 95 KT 110 MPH 36H 09/1200Z 24.4N 126.8W 105 KT 120 MPH ... NEAR SOUTHERN RYUKYU ISLANDS 48H 10/0000Z 25.9N 124.7W 125 KT 145 MPH ... NEAR SOUTHERN RYUKYU ISLANDS / EAST CHINA SEA 72H 11/0000Z 27.8N 122.1W 115 KT 135 MPH ... NEAR CHINA ... LANDFALL ON ZHEJIANG, CHINA ANTICIPATED DURING THIS TIME ... 96H 12/0000Z 29.7N 120.5W 55 KT 65 MPH... INLAND 120H 13/0000Z 32.3N 120.7W 30 KT 35 MPH ... INLAND $$ Forecaster TheAustinMan